Clinical Briefs

Monica Preboth

Am Fam Physician. 2001 Aug 1;64(3):516.

Use of Helical CT for Lung Cancer Screening

The Health Technology and Advisory Committee (HTAC) has published a report on the use of helical computed tomography (CT) for lung cancer screening in asymptomatic patients. HTAC was established in 1992 by the Minnesota state legislature. It is an independent, nonpartisan advisory body that evaluates new and emerging health care technologies based on existing scientific research and technology assessments.

According to HTAC, the overall prognosis for lung cancer is generally poor. The five-year survival rate is less than 15 percent. While evidence suggests that early detection can significantly increase long-term survival, a number of professional organizations, the National Cancer Institute and the U.S. Preventive Services Task Force recommend against routine screening with chest radiography or sputum cytology of asymptomatic persons for lung cancer, and stress that the highest priority should be given to programs for smoking cessation. Recently, helical CT has been proposed as a way to screen for early lung cancer lesions in asymptomatic, high-risk persons. These organizations have not yet made a recommendation about the use of helical CT as a screening tool.

Based on their findings, the HTAC has made the following conclusions and recommendations:

While helical CT scanning may detect pulmonary nodules at an earlier stage, there is no evidence from randomized controlled trials that screening asymptomatic persons for lung cancer increases actual survival time or reduces mortality.

The use of helical CT is valuable in persons with specific concerns or for diagnosis of pulmonary lesions in symptomatic persons.

Because of the high false-positive rate associated with helical CT, detection of lung cancer by routine screening of asymptomatic persons may cause a cascade of unnecessary care and secondary testing.

Physicians should use a helical CT scan for specific indications in individual patients.

The potential long-term efficacy and cost-effectiveness of helical CT scanning should be established through additional published studies before becoming common practice.

FDA Approves Treatment With Botulinum Toxin Type A

The U.S. Food and Drug Adminis tration (FDA) has granted approval to market botulinum toxin type A (Botox) purified neurotoxin complex for the treatment of adult patients with cervical dystonia.

Cervical dystonia is a neurologic movement disorder characterized by involuntary muscle contractions that force the head and neck into abnormal and sometimes painful positions. According to the manufacturer, injection of botulinum toxin type A reduces the severity of the abnormal head position and neck pain by blocking the release of the neurotransmitter acetylcholine from the peripheral nerve terminal to the muscle.

The approval of botulinum toxin type A was based on results of a phase III randomized, multicenter, double-blind, placebo-controlled clinical trial. Results showed that the patients who received botulinum had significantly greater improvements in decreasing the severity of abnormal head position and neck pain than the patients who received placebo.

According to the manufacturer, the adverse effects most often reported in the clinical trials were dysphagia, upper respiratory infection, neck pain and headache. Care should be taken when administering botulinum toxin type A to patients with peripheral motor neuropathic diseases, such as amyotrophic lateral sclerosis and motor neuropathy, or neuromuscular junctional disorders, such as myasthenia gravis or Lambert-Eaton syndrome. The manufacturer reports that patients with neuromuscular disorders may be at increased risk of clinically significant systemic effects including severe dysphagia and respiratory compromise from typical doses of the medication.